Preparation of Nano BaTiO_3-Based Dielectric Ceramics by Different Sintering Methods

摘要

Microstructure control in thin-layer multilayer ceramic capacitors (MLCCs) is one of the nowadays challenges for increasing capacitive volumetric efficiency and high voltage dielectric properties. In this paper, the ultrafine-grained BaTiO_3 dielectric ceramics with uniform grain size distribution were prepared by chemical coating approach. The doping effects of rare-earth element (Ho) on the microstructures and dielectric properties of the ceramics were investigated. The addition of Ho in nano BaTiCvbased ceramics was found to improve the temperature coefficient of capacitance (TCC) performance, which could be attributed to a significant reduction in the grain size. Moreover, the effects of two-step sintering (TSS) method on the microstructures and dielectric properties, compared with conventional sintering (CS) method, were also discussed. The dielectric constant of ceramics sintered by the TSS method was higher than that of ceramics prepared by CS method. The results reveal that the adoption of TSS method could control the grain size and suppress the abnormal grain growth more effectively, which improves the TCC characteristics.